Generally, an analog signal should be processed based on an analog-to-digital conversion in an electronic device, and then a processor of the electronic device can perform the subsequent operations based on the digital signal obtained through the analog-to-digital conversion. In particular, when an analog signal to be converted is small, the analog signal needs to be amplified. For example, in a typical detection device or detection system, the detection signal measured by a sensor is usually small, such as several hundred millivolts (mV); therefore, before being processed by the processor, the detection signal needs to be amplified and then analog-to-digital converted, to obtain the digital value corresponding to the amplified detection signal.
However, according to the prior art, if the conversion accuracy of an analog-to-digital converter is to be improved, then it needs to increase the bit number of the analog-to-digital converter, which increasing the cost.